In mobile communications, the term “combinational services” refers to the combining of traditional voice call services with additional services, such as video sharing, file sharing, multimedia messaging, and the like, which enhance the overall user experience. Not all networks, however, support combinational services. For instance, a Universal Mobile Telecommunications (UMTS) network will support IP Multimedia Subsystem (IMS) services, whereas a Global System for Mobile Communications (GSM) network will not. Therefore, when a mobile device on a UMTS network engages in a call with a mobile device on a GSM network, the call is limited to a voice call.
It is commonplace, however, for devices to roam across networks. A device can begin a call on one type of network and then roam outside of its network coverage area and be handed off to another network. When this occurs, a device's capabilities can change. If a device on a GSM network moves to a UMTS network, then it is moves from a network that is not capable of supporting combinational services to a network that is capable of supporting combinational services. Nevertheless, mobile devices combinational are only set up at the beginning of a call. Therefore, a device moving from a GSM network to a UMTS network, during a call, will not be able to utilize combinational services because they were not set up at the beginning of the call. Accordingly, what is needed is a system and method to provide a capability update during a call.